Ultrasonic energy has been established as a viable means of removing obstructive matter (e.g., atherosclerotic plaque or thromboembolic material) from blood vessels. Examples of ultrasonic devices purportedly useable to remove or ablate vascular obstructions are found in U.S. Pat. Nos. 3,433,226 (Boyd), 3,823,717 (Pohlman, et al.), 4,808,153 (Parisi), 4,936,281 (Stasz), 3,565,062 (Kuris), 4,924,863 (Sterzer), 4,870,935 (DonMichael, et al.), 5,069,664 (Suess, et al.) and 4,920,954 (Alliger, et al.), as well as other patent applications WO 87-05739 (Cooper), WO 89-06515 (Bernstein, et al.), WO 90-0130 (Sonic Needle Corp.), EP 316,789 (DonMichael, et al.), DE 3,821,836 (Schubert), DE 2,438,648 (Pohlman) and EP 0443256 A1 (Baruch).
U.S. patent application Ser. No. 07/640,190 entitled ULTRASONIC ANGIOPLASTY DEVICE INCORPORATING IMPROVED TRANSMISSION MEMBER AND ABLATION PROBE, of which this application is a continuation-in-part, describes an ultrasound catheter device comprising a flexible tubular catheter having a wire-like elongate ultrasound transmission member which extends longitudinally through the catheter. Ultrasonic energy may be passed through the ultrasound transmission member to effect ultrasonic ablation or destruction of unwanted material located adjacent the distal end of the catheter.
Although the disclosure of U.S. patent application Ser. No. 07/640,190 includes certain configurational and/material modifications intended to improve the flexibility or bendability of the ultrasound transmission member, there remains a need in the art for further improvements whereby the flexibility or bendability of an ultrasound catheter may be optimized while maintaining the requisite efficiency of energy transmission through the length of the catheter.